socket编程之select多路复用

你的名字 2022-09-24 12:26 140阅读 0赞

/*************************************************************************
     *  Copyright (C): 1540999272@qq.com
     *  Filename:      server.c
     *  Author:        Lu Zengmeng
     *  Description:   
     *  Creat Time:    2016-07-19 12:08
     ************************************************************************/
    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <arpa/inet.h>
    #include <netinet/in.h>
    #include <strings.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <string.h>
    #include <fcntl.h>
    #include <sys/stat.h>
    #include <time.h>
    
    #define PORT             8003
    #define BUF_LEN          128
    #define BACKLOG          5
    
    int main(int argc, char *argv[])
    {
            int                    sock_fd;
            int                    conn_fd;
            int                    yes = 1;
            struct sockaddr_in     my_addr;
    
        bzero(&my_addr,sizeof(my_addr));
        my_addr.sin_family        = AF_INET;
        my_addr.sin_port          = htons(PORT);
        my_addr.sin_addr.s_addr   = INADDR_ANY;
    
    
        if (-1 == (sock_fd = socket(AF_INET, SOCK_STREAM, 0)))
        {
            perror("socket");
            exit(1);
        }
        
        if (-1 == setsockopt(sock_fd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int)))
        {
            perror("setsockopt");
            exit(1);
        }
    
        if (-1 == bind(sock_fd, (struct sockaddr *)&my_addr, sizeof(my_addr)))
        {
            perror("bind");
            exit(1);
        }
    
        if (-1 == listen(sock_fd, BACKLOG))
        {
            perror("listen");
            exit(1);
        }
    
        printf("listenning...\n");
    
        fd_set         fds; //创建select所要检查的集合fds
        int            max_fd;
        int            ret;
        int            i;
        int            conn_amount = 0;
        int            fd_all[BACKLOG]= {0,}; //用来存放需要通信的多个socket描述符
        struct timeval tv;
        char           recv_buf[BUF_LEN];
    
        max_fd = sock_fd;
    
        while(1)
        {
            FD_ZERO(&fds); //初始化关注列表
            FD_SET(sock_fd,&fds); //将listen的sock_fd加入关注
    
            tv.tv_sec  = 5;
            tv.tv_usec = 0;
    
            for(i=0;i<BACKLOG;i++) //将所有需要通信的socket描述符存入fd_all数组
            {
                if(fd_all[i] != 0)
                    FD_SET(fd_all[i],&fds);
            }
    
            ret = select(max_fd+1,&fds,NULL,NULL,&tv);
            if(ret < 0)
            {
                perror("select");
                break;
            }
    
            else if(0 == ret)
            {
                printf("timeout\n");
                continue;
            }
    
            for(i=0;i<conn_amount;i++)
            {
                if(FD_ISSET(fd_all[i],&fds)) //检查已建立的连接是否有数据请求
                {
                    ret = recv(fd_all[i],recv_buf,BUF_LEN,0);
                    if(ret <= 0)
                    {
                       printf("client[%d] closed \n",fd_all[i]);
                       close(fd_all[i]);
                       FD_CLR(fd_all[i],&fds);  //清除已关闭的socket描述符
                       fd_all[i] = 0;
                       //conn_amount--;
                    }
                    else
                    {
                        recv_buf[ret] = '\0';
                        fflush(stdout);
                        printf("%s from client[%d]\n",recv_buf,fd_all[i]);
                    }    
                }
            }
    
            if(FD_ISSET(sock_fd,&fds))  //检查是否有连接请求
            {
                conn_fd = accept(sock_fd,NULL,NULL);
                if( conn_fd < 0)
                {
                    perror("accept");
                    continue;
                }
    
                if(conn_amount < BACKLOG)
                {
                    fd_all[conn_amount++] = conn_fd;  //将新建立的连接加入关注
                    printf("new connection client[%d] \n",conn_fd);
    
                    if(conn_fd > max_fd)  //重新设置max_fd
                        max_fd = conn_fd;
                }
    
                else
                {
                    printf("max connections arrive,exit\n");
                    close(conn_fd);
                    break;
                }
            }
    
            printf("Client amount: %d\n",conn_amount);
            for(i=0;i<BACKLOG;i++)
            {
                if(fd_all[i]!=0)
                    printf("client[%d] \n",fd_all[i]);
            }
            printf("\n");
    
        }
    
        for(i=0;i<BACKLOG;i++)
        {
            if(fd_all[i] != 0)
                close(fd_all[i]); //关闭所有fd
        }
    
            return 0;
    }